Errors in medication provided to a patient are recognized as a serious, and potentially avoidable, problem associated with the delivery of health care.
Medication errors are estimated to account for 7,000 deaths annually, and adverse drug events cause more than 770,000 injuries and deaths each year. Patients who suffer from unintended drug events remain in the hospital an average of 8 to 12 days longer than patients who did not experience such mistakes. Two recent studies, one conducted in Colorado and Utah and the other in New York, found that adverse events occurred in 2.9 and 3.7 percent of hospitalizations, respectively.
Infusion devices are believed to account for up to 35% of all medication errors that result in significant harm (Class 4 and 5). Mistakes typically arise from manually programming incorrect infusion parameters, and the failure to ensure the right patient receives the right medication. The most common error is manually programming infusion parameters such as delivery rate, drug, and drug dose, into the device.
Unfortunately, there is currently no commercially available device capable of reliably determining both the identity and concentration (and thus dosage) of a wide variety of unknown intravenous fluids as they are being delivered to a patient.
Although systems for verifying the presence of a drug or its concentration have been proposed, the majority of these systems rely solely on optical methods (such as optical spectroscopy). For example, U.S. Pat. No. 6,847,899 to Allgeyer et al. describes a spectroscopic analysis device for identifying medications in an IV solution. Similar systems are described in U.S. Pat. No. 7,154,102 to Poteet et al. (florescence spectroscopy), PCT/US2007/087062 and PCT/US2006/036612 by Potuluri et al. (verification of solid drug identity by optical spectroscopy) and U.S. Pat. No. 7,317,525 to Rzasa et al.
Because these systems rely on spectroscopic analysis, they typically suffer from the limitations inherent in optical systems. These limitations may include a limited ability to distinguish between compounds, and particularly mixtures of compounds having multiple components, as well as difficulty in reliably distinguishing concentrations of different compounds.
Described herein are admittance spectroscopy devices and methods that use multiple electrical admittance measurements to determine both the identity and concentration of one or more components of a medical solution such as an intravenous solution. The inventors believe that this is the first successful application of admittance spectroscopy to determine the identity and concentration of a medical fluid. Although admittance spectroscopy has been previously described in other contexts, primarily for scientific research on material characterization and particularly solid-state materials, including the characterization of dielectrics, semiconductors, electrolytes and their interfaces with metals and each other. Sensors based on admittance spectroscopy include chromatography detectors and pH sensors, enzyme-based sensors, blood-glucose sensors and urease-based sensors. However, none of these sensors are capable of determining the identity and concentration of unknown components in an aqueous solution.
The devices, systems and methods described herein may address some or all of the problems described above, and may provide systems, devices and methods for the accurate and reliable determination of one or more compounds in a solution.